It is often desirable to know the location or position of a wireless device in a network, with the terms “location” and “position” being synonymous and used interchangeably herein. For example, a user may utilize a wireless device to browse through a website and may click on location-sensitive content. A web server may respond to this click by querying the network for the position of the wireless device. The network may initiate position processing with the wireless device in order to ascertain the position of the wireless device. The network may return a position estimate for the wireless device to the web server, which may use this position estimate to provide appropriate content to the user. There are many other scenarios in which knowledge of the position of a wireless device may be useful such as when a user of the wireless device instigates an emergency call, needs directions to move to a different location or needs to be located or tracked by another authorized user.
A message flow (which may also be called a call flow or a procedure) is typically executed in order to obtain a position estimate for a wireless device and to send this position estimate to an external client entity, e.g., a web server. Various messages are typically exchanged between one or more network entities, the wireless device, and the external client entity for the message flow. These messages ensure that each entity is provided with pertinent information, or can obtain this information from another entity, in order to carry out positioning for the wireless device and/or deliver the position estimate to the client entity.
One commonly used solution for location based services is known as Secure User Plane Location (SUPL) as defined by the Open Mobile Alliance (OMA). With the SUPL solution, a wireless device, known as a SUPL Enabled Terminal (SET), and a location server, known as a SUPL Location Platform (SLP), interact using the SUPL User Plane Location Protocol (ULP) to obtain the location of the SET on behalf of the SET and/or SLP. Obtaining the location of the SET typically includes identifying one or more than one position method by the SLP, identifying a positioning protocol that will enable information related to the identified position method(s) to be exchanged between the SET and SLP, and identifying positioning capabilities of the SET that may be applicable to the identified positioning protocol and/or identified position method(s).